Vent valve for gas pressure regulators and pressure regulator equipped with said vent valve

Abstract

The invention is a gas vent valve ( 10 ) for a gas pressure regulator ( 1 ), comprising: a tubular body ( 11 ) developed between two opposite openings ( 11 a, 11 b ); a shutter body ( 12 ) biased towards a position in which a first opening ( 11 a ) of the tubular body ( 11 ) is closed and movable from the closed position towards an open position for opening the first opening ( 11 a ) due to the effect of a pressure acting from the outside of the tubular body ( 11 ) through the first opening ( 11 a ); constraining means ( 13 ) configured so as to prevent the movement of the shutter body ( 12 ) from the closed position towards the open position when the ambient temperature exceeds a predefined value.

The invention claimed is: 
     
       1. A gas vent valve for a gas pressure regulator, comprising:
 a tubular body provided with a first opening and a second opening opposite thereof; 
 a shutter body movably mounted to move between a closed position, in which said shutter body closes said first one opening, and an open position, in which said shutter body opens said first opening, said shutter body being constantly biased towards said closed position, said shutter body being biased towards said open position upon a pressure acting from the outside of said tubular body through said first opening, 
 wherein said second opening is in communication with said first opening so that, when a gas coming from said first opening opens said shutter body, said gas flows through said second opening; and 
 further comprising constraining means for preventing said shutter body from moving from said closed position towards said open position when the ambient temperature exceeds a predefined value, said constraining means comprising:
 thrust means at least partially disposed within said tubular body and suited for maintaining said shutter body in said closed position, said thrust means being disposed between said first opening and said second opening; and 
 stop means suited for inhibiting said thrust means, said stop means being configured so as to release said thrust means when the ambient temperature exceeds said predefined value. 
 
 
     
     
       2. The gas vent valve according to  claim 1 , wherein said thrust means comprise a shaped body associated with elastic means suited for thrusting said shaped body against said shutter body, said stop means comprising a counteracting body constrained to said tubular body and suited to maintain said shaped body in a spaced position with respect to said shutter body against the action of said elastic means, said counteracting body being configured to yield when the ambient temperature exceeds said predefined value. 
     
     
       3. The gas vent valve according to  claim 2 , wherein said shaped body comprises a thread, said counteracting body comprising a counter thread screwed to said thread. 
     
     
       4. The gas vent valve according to  claim 2 , wherein said elastic means comprise a spring. 
     
     
       5. The gas vent valve according to  claim 2 , wherein said counteracting body is made of a plastic material. 
     
     
       6. The gas vent valve according to  claim 5 , wherein said plastic material is a acetal-based or nylon-based material. 
     
     
       7. The gas vent valve according to  claim 1 , wherein said tubular body comprises an external thread so that said tubular body can be screwed to a pressure regulator. 
     
     
       8. A gas pressure regulator comprising:
 a containment body that defines a flow duct for a gas and a motorization chamber communicating with said flow duct; 
 vent means suited for placing said motorization chamber in communication with the outside of said containment body and comprising a vent hole suited to place said motorization chamber in permanent communication with the outside of said containment body; 
 a first membrane arranged in said motorization chamber in such a way as to divide said motorization chamber into a first zone, communicating with said flow duct, and into a second zone, communicating with said vent means; 
 a shutter arranged in said flow duct and associated with said first membrane in such a way that the movements of said first membrane in two opposite directions cause corresponding movements of said shutter intended to increase or, respectively, decrease a gas passage cross section along said flow duct, wherein said gas vent means comprise a vent valve according to  claim 1 . 
 
     
     
       9. The regulator according to  claim 8 , wherein said vent hole has a smaller gas passage cross section compared to that of said vent valve. 
     
     
       10. The regulator according to  claim 8 , further comprising a second membrane interposed between said first membrane and said vent means and being configured so as to resist a temperature exceeding said predefined value. 
     
     
       11. The gas vent valve according to  claim 1 , further comprising a gas pressure regulator secured to the tubular body. 
     
     
       12. A gas pressure regulator comprising:
 a containment body having an inlet, an outlet, and a flow duct that extends therebetween, the containment body also having a motorization chamber; 
 a first membrane disposed within the containment body and dividing the motorization chamber into a first zone that communicates with the flow duct and a second zone; 
 a shutter disposed in the flow duct and associated with the first membrane so that movement of the first membrane in two opposite directions causes corresponding movement of the shutter; and 
 a first gas vent valve comprising: 
 a tubular body having a first opening and a second opening spaced apart from the first opening, the tubular body being secured to the containment body so that the first opening is in communication with the second zone of the motorization chamber; 
 a shutter body movable between a first position wherein the shutter body closes the first opening and a second position wherein the shutter body opens the first opening, the shutter body being resiliently biased towards the closed position, the first opening being in communication with the second opening when the shutter body is in the second position; and 
 a constraining member that prevents the shutter body from moving from the first position toward the second position when the ambient temperature exceeds a predefined value, the constraining member comprising:
 a thrust member at least partially disposed within the tubular body and suited for maintaining the shutter body in the closed position, the thrust member being disposed between the first opening and the second opening; 
 a stop member that inhibits movement of the thrust member, the stop member releasing the thrust member when the ambient temperature exceeds the predefined value; and 
 a spring that moves the thrust member when the thrust member is released by the stop member, the spring forcing the thrust member against the shutter body so as to hold the shutter body in the first position. 
 
 
     
     
       13. The gas pressure regulator according to  claim 12 , further comprising a second vent valve spaced apart from the first vent valve, the second vent valve being in communication with the second zone of the motorization chamber.